This article presents an empirical model for the noise of the acoustic underwater channel in shallow water from the analysis of field data measurements. A probability density function for the noise amplitude distribution is proposed and the associated likelihood functions are derived. As a result, an expression to the probability of symbol error for binary signaling is presented for the channel...

In this paper a novel algorithm has been designed to get rid of the problem of over-enhancement found in Mix CLAHE specifically for underwater images. The underwater image is suffering from low contrast and resolution because of dispossessed visibility circumstances, hence a subject identification become typical task. The processing of underwater image captured is important because the grade of...

History of underwater diving dates back to antiquity. Breath-hold technique in diving was known to the ancient nations. However, deep diving progressed only in the early decades of the 19th century as the result of advancements in efficient underwater technologies which subsequently led to invention of sophisticated sets of scuba diving in the 20th century. Currently, diving is performed for va...

Deployment efforts of underwater acoustic sensor networks have been impeded by the prohibitive monetary cost and high power consumption of existing acoustic hardware, which typically targets deep water long range communication. To address this issue, we propose software-driven underwater networks that rely on widely available speakers and microphones in electronic devices, coupled with software...

This paper designs an underwater acoustic communication system based on tamed spread spectrum and Frequency Hopping Multiple Access (FHMA) for multiple underwater vehicles. In this system, multiple underwater vehicles can communicate with the console on the water surface simultaneously successfully. The communication system is composed of tamed spread spectrum modulation and demodulation, frequ...

Underwater vision is a significant issue in ocean engineering. Atmospheric images and underwater images undergo from medium scattering and light distortion, leading to the low contrast and visibility of images. However, there are some different characters of the underwater images. Firstly, catching pictures submerged is troublesome, because of the weakening caused by light that is reflected fro...

In underwater computer vision, images are influenced by the water in two different ways. First, while still traveling through the water, light is absorbed and scattered, both of which are wavelength dependent, thus create the typical green or blue hue in underwater images. Secondly, when entering the underwater housing, the rays are refracted, affecting image formation geometrically. When using...

Underwater birthing has become a popular birth practice in some areas of the country. Although many of these deliveries occur in a home birth setting, the practice has also been implemented in hospitals and birthing centers. There is continued controversy about the risks and benefits of underwater birthing (as opposed to hydrotherapy during labor), and many risk managers are unaware of these po...

Underwater environment poses a difficult challenge for autonomous underwater navigation. A standard problem of underwater vehicles is to maintain it position at a certain depth in order to perform desired operations. An effective controller is required for this purpose and hence the design of a depth controller for an unmanned underwater vehicle is described in this paper. The control algorithm...